Spark advance control mechanism for spark ignition internal combustion engines



1959 A. (5. DE CLAIRE, JR. L 2,871,840

SPARK ADVANCE CONTROL-.MECHANISM FOR SPARK IGNITION INTERNAL COMBUSTION ENGINES Filed July 9, 1956 42 44 I FIGJ. 68 ,92 82 I02 94 I I ,23 I00 96 24 50 w 42 4o so 72 76 80 44 52 F 7 88 39 f on.

PUMP

3 7o 9 86 o 3 2 90 U 26 a 52 4s 36 i I04 34 32 5 2 mmvroxs ALTON s. DEGLAIRE JR. FIG 2 'ATTO R NEYS M/ roe United States Patent SPARK ADVANCE CONTROL MECHANISM FOR IGNITION INTERNAL COMBUSTION Alton G. De Claire, Jr., Harper Woods, and Richard E. Leibold, Detroit, Mich., assignors to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Application July 9, 1956, Serial No. 596,473

21 Claims. (Cl. 123117) It 'is a feature of the present inventionto'provide a a driven shaft in axial alignment with a shaft having a cam thereon for controlling spark ignition, in combina tion with a coupling sleeve having a slidable spline connection with both of said shafts, said spline connection having difierent angles of inclination, and fluid pressure actuated means responsive to variable engine conditions for effecting axial movement of said coupling sleeve relative to said shafts.

Other objects and features of the invention will become apparent as the description proceeds, especially when I taken in conjunction with the accompanying drawings,

wherein:

Figure 1 is a plan view of a distributor with the cover removed and parts broken away.

Figure 2 is a section on the line 2-2, Figure 1.

Figure 3 is an enlarged fragmentary vertical sectional view of the mechanism for controlling spark advance.

Figure 4 is a fragmentary sectional view of the pressure control mechanism of the distributor.

Referring first to Figure 1, the ignition distributor comprises a spring pressed arm pivoted as indicated at 12 to a supporting plate 14 located in a housing indicated at 15 and having a contact 16 at the end of the arm. Contact 16 is connected to terminal 17 by means of the conductive spring 18 which serves as a means for biasing the spring arm counterclockwise as seen in Figure 1. A stationary contact 20 suitably grounded to plate 14 is provided. A condenser 21 is connected to the terminal 17 by wire 22 to provide arc protection for contacts 16 and 20. A cam 23 carried by a shaft 24 is provided against which a portion of the arm 10 is urged by the spring, and as the cam rotates contact is rapidly made andbroken between contacts 16 and 20.

In operation the cam 23 is rotated by a shaft 26, the

.shaft 26 drivenby gearing 27 connected to a rotating part of the engine such for example as the cam shaft.

It is desirable to effect angular adjustment between the cam 23 'and the shaft 26 in accordance with variable engine conditions. In the past, means have been provided responsive to engine speed and manifold vacuum for effecting automatic control of spark advance by angularly adjusting the cam 23 with reference to the shaft 26. Specifically, such a construction is shown in Larges application Serial No. 522,791 entitled Spark Distributor, filed July 18, 1955. In this prior construction the forces available for effecting angular adjustment of the cam were those developed mechanically by centrif- 2,87l,840 Patented Feb. 3, 1959 v ugal action and forces dependent on changes in manifold vacuum.

In accordance with the present invention these forces are used as control forces and a device which is essentially a servo mechanism operating from oil delivered from the oil pump of the internal combustion engine is employed. I

Referrin now to Figures 2-4 the ignition distributor mechanism includes a pair of centrifugal weights 30 movable outwardly under centrifugal action against the opposing force of springs 31 and 32 received in casing members 33. The centrifugal weights include pressure chambers 34 closed by flexible diaphragms 36 to which are secured movable sleeves 38, best seen in Figure 1. It will be observed that each of the sleeves 38 includes a laterally offset portion having an ear 42 provided with an elongated opening 44.

A pair of the centrifugal weights 30 are provided in diametrically opposed relation and accordingly a pair of the laterally offset ears 42 are provided which are movable generally toward and away from each other tangentially of a circle concentric with the axis of the shaft carrying the cam 23.

Upon an increase in speed, the centrifugal weights 30 move radially outwardly, thus eifecting radial outward movement of the sleeves 38. Also, variations in manifold vacuum, applied to the interior of the chamber 34 through passage means indicated generally at 46, eflects movement of the diaphragm 36 against the action of the compression' spring shown in the chamber. f. 5

Accordingly, the movement of the sleeves 38 lisrthe arithmetical sum or difference of the movement of the weightsby centrifugal force and the displacement of the diaphragms by variations in manifold vacuum;

Referring now to Figure 3 the laterally offset portion 40 with the ear 42 provided with the elongated opening 44 is associated with an arm rotatably secured on the shaft 26 by means of a depending pin 52 carried by the arm 50 and extending into the slot 44. Accordingly, as the sleeves 38 move radially of the shaft 26 in accordance with variations in engine conditions, the pins- 52 in the slots 44 result in angular movement of the arms 50 with reference to the shaft 26. In accordance with the present invention the movement of the arms 50 is substantially unopposed and accordingly, the arms 50 move freely to accurately predetermined positions in accordance with the instantaneous values of variable engine conditions.

In order to utilize movement of the arms 50 to effect the required adjustment of the cams 23, the shaft 24 which carries the cam is recessed at its lower endas indicated at 54, and receives the reduced upper end portion 56 of the shaft 26. Thus, the shaft 24 is piloted on the upper end of the shaft 26.

Means for driving the shaft 24 in all positions of angular adjustment relative to the shaft 26 comprises essentially a splined sleeve 60. At its upper end the sleeve 60 has an internal spline 62 slidable longitudinally with anexternal spline 64 on the lower end of 11168113111 14. In addition, the sleeve 60 includes a lower .portion 66 having an internal spline 68 longitudinally *slidable in a corresponding external spline 70 provided adjacent the upper end of the shaft 26, As best illustrated in Figure 2, the inclination of the internal and external splines 68 and 70 may be about 20 degrees.

For convenience the internal and external splines 62 and 64 are preferably straight or parallel to the axis of the coupled members. Accordingly, if the sleeve construction 60 is moved axially with reference to both of the shafts 24 and 26, it will be rotated or angularly adjusted with reference to the shaft 26 and its straight spline connection with the shaft 24 will result in angular adiustment thereof relative to the shaft 26, while at the same time maintaining driving relationship between the parts.

In accordance with the present invention, forces are developed effecting axial movement of the coupling sleeve assembly 60 under the control of the speed and load sensing mechanism including the weights 30 and diaphragms 36.

This mechanism includes an annular plate 72 connected to an annular spring seat 74 engaging a compression spring 76 tending to move the assembly comprising the plate 72 and spring seat 74 downwardly. Extending between the spring seat 74 and the coupling sleeve assembly 60 is hearing means indicated generally at 78. As best seen in Figure 2, the plate 72 has secured thereto a flexible diaphragm 80, a portion of which is indicated in Figure 3. The ignition distributor housing includes a stationary inwardly extending annular ledge portion 82 toward and away from which the plate 72 is movable.

Inasmuch as the coupling sleeve assembly 60 is rotatable with the shaft 26, and the assembly comprising the plate 72 and spring seat 74 are not rotatable, and since the housing ledge portion 82 is not rotatable, suitable seals indicated generally at 84 are provided.

The space 86 intermediate the annular plate 72 and the housing ledge portion 82 is connected as indicated in Figure 2 to a conduit 88 extending to the oil pump of the internal combustion engine (indicated diagrammatically at 89 in Figure 2) so that a supply of oil under substantially constant elevated pressure is available at all times within the chamber 86. The inlet for oil under pressure includes a restriction 90 so that a relatively restricted flow of oil is permitted.

The sleeve construction 60 includes depending tubular portions 92 including radially outwardly extending portions 94 closed at their outer ends as by plugs 96. Adjacent the ends of the radially extending tubular portions 94 are provided flattened side portions 98 (see Figure 4) provided with outlet ports 100. The arms 50 at their outer ends include upwardly extending flat valve portions 102 adapted to overlie the ports 100. The valve portions 102 have substantial axial extent to cooperate with the ports 100 throughout a substantial range of axial movement of the sleeve assembly 60.

In operation the position of the coupling sleeve 60, and hence the position of angular adjustment between the shafts 24 and 26, is controlled by varying the pressure within the chamber 86. The spring 76 exerts a substantially constant force on the sleeve and movable plate assembly and the parts are dimensioned so that when fluid from the oil pump is trapped within the chamber 86, the force of the spring is overcome and the sleeve and connected elements move upwardly. However, upward movement of the sleeve and connected elements results in rotation of the sleeve, the shaft 24,

and the radially extending tubular arm 94. If it is assumed that the parts are in the relative position illustrated in Figure 4, the pressure within the chamber 86 is just suflicient to overcome the force of the spring 76, the rate of flow of oil under pressure into the chamber 86 being equal to the rate of flow of oil under pressure out of the port 100 past the valve 102. If now, do to a change in one of the variable engine conditions, the valve 102 moves away from the port 100, pressure within the chamber 86 is reduced and the spring effects downward movement of the sleeve and associated structure. This downward movement of the sleeve and associated structure results in rotational movement of the arm 94 in a direction causing it to follow the valve 102 and such movement will continue until the arm reaches a position with respect to the new position of the valve 102 such that the pressure conditions within the chamber 86 again stabilize at the value required to balance the force of the spring. Conversely, if the valve 102 is between a par moved by the condition responsive mechanism toward the arm 94, escape of fluid from the chamber 86 is prevented and pressure within the chamber builds up, thus shifting the sleeve upwardly against the spring 76 and eifecting a reverse angular adjustment of the cam 23. This in turn is accompanied by rotation of the arm 94 away from the valve 102. Accordingly, the construction operates as a servo mechanism in which the valve 102 controls the position of the arm 94 in angular movement, and its relative angular movement efiects axial movement thereof relative to both shafts 24 and 26.

Referring again to Figure 2, the oil under pressure which escapes from the port 100, drops into a sump 104 from which it may return by gravity through a passage 106 to the crankcase.

It will be observed that the sectional view of Figure 2 is taken in two planes disposed at right angles to each other. One plane passes through the control mechanism including the centrifugal weight 30 and the diaphragm 36, and the other plane passes through the radially extending arm 94. It will of course be appreciated that two centrifugal weights 30 are provided connected to be rotated by the shaft at positions degrees apart. In similar manner, the control mechanism includes, for balancing purposes, two of the radially extending. arms 94 and two of the radially extending arms 50, one or both of which carry the valve 102.

By employing the present construction the forces available to effect positiv'e adjustment of the cam relative to the shaft 26 are relatively large. On the other hand, the forces required to effect. controlling movements of the arm 50 are relatively small. 1 This is. essentialbecause while substantial-forces. are developed in the system, it 'is very desirable-for the control -to"be responsive to very slight changes :in the controlling forces. 1

The servo mechanism employsasr'the source of energy which it controls, the lubricatingoil pump which'is-a part of the internal combustion engine to' which the ignition distributoris'applied.:.-. I 5

While the actual condition responsive mechanismlias been illustrated and described, it will be appreciated that the invention is primarily concerned with power means for etfecting adjustments of sparkadvanceafidthaFthe actual condition responsive mechanism which effects movement of the control valve 102 may be of widely different types.

The drawings and the foregoing specification constitute a description of the improved spark advance control mechanism for spark ignition internal combustion engines in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What we claim as our invention is:

1. Spark advance mechanismfor an internal combustion engine having an oil pump comprising a drive shaft adapted to be connected to the e'ngin'efor rotation thereby, a timing cam shaft disposed coaxially with said .drive shaft, an axially movable sleeve coupling said drive shaft and timing cam-shaft and having differently inclined splined connections with both shafts whereby axial movement of said sleeve results in angular movement of said timing cam shaft relative to said driveshaft, means responsive to a variable engine condition for moving said sleeve axially, said means comprising an annular chamber surrounding said drive shaft having an axially movable wall connected to said sleeve, a spring'op'posing movement of said wall in the direction which enlarges said chamber;said chamber including means providing a fluid escape port, a valve movable toward and'away from said port, means for movingsaid valve in accordance with a variable engine condition, and means for introducing 'oil from said oil pumpinto said chamber. v

2. Serve mech "sm for effecting angular adjustment of'rotary coaxial shafts comprising a'sleeve splined to both of said shafts with splines of difierent angularity, a fluid motor operatively connected to said sleeve to effect axial adjustment thereof, said motor including a regulating valve rotatable with said shafts and controlling operation of said motor and means independent of said splines for driving one of said shafts in rotation.

3. Servo mechanism for effecting angular adjustment between a pair of coaxial shafts comprising a sleeve splined to both of said shafts with splines of, different angulan'ty, a fluid motor connected to said sleeve to move said sleeve axially of said shafts, resilient means connected to said sleeve to oppose movement thereof by said motor, means for supplying fluid under pressure to said motor, means providing an outlet port from said motor movable with said sleeve, a valve mounted on one of said-shafts for angular adjustment about the axis thereof toward and away from said port, and means for moving said valve.

-4; Servo mechanism for effecting angular adjustment between 'a pair of coaxial shafts comprising a sleeve splined to both of said shafts with splines of different angularity, a fluid motor having an expansible chamber including a portion connected to said sleeve to move said sleeve axially of said'shafts, resilient means connected to said sleeve'to oppose movement thereof by said motor, means fo'r -supplying fluid under pressure to said motor, mean's'providing an outlet port from said motor movable with saidsleeve, a valve m'ounted on one of said shafts for angularadjust'ment about the axis thereof toward and away from said port,- and means for moving said valve. 'Sr- Servo mechanism for effecting angular adjustment between -'a"--'p'a'ir' of coaxial shafts comprising a sleeve splined to bo'th' of said shafts with splines of different angularity, a'-'-fluidmotor havin'g an expansible chamber including a portion connected to said sleeve to move said sleeve of. said shafts, resilient means connected to said sleeve'to oppose 'movement'thereof by said motor, means for supplyingfluidunder pressure to said motor,

meansgproviding an outlet portfgomsaid motor movable- ;with said sleeve a sleeve arm extending radially from said sleeve'sha ving a passage communicating with the interior of'saidchamber and having an outlet port facing circumferentiallyl with respect to said sleeve, the angular splined connections. with oneof said sleeves providing for relative angularjmovement therebetween as a consequence of relative faxial movement therebetween, a valve arm carried by saidone shaft having a valve portion overlying said port, and means for movingsaid valve arm relative to said one shaft to vary pressure within said chamber to effect axial movement of said sleeve and said sleeve arm with consequent valve arm following movement by said sleeve arm.

6. Servo mechanism as defined in claim 5 in which said shafts are connected between a rotating part of an internal combustion engine and an engine timing cam, and in which the chamber is adapted to be connected to the oil pump of the engine.

7. Servo mechanism for effecting angular adjustment between a pair of coaxial shafts comprising a sleeve splined to both of said shafts with splines of different angularity, a fluid motor comprising an annular expansible chamber surrounding the axis of said shafts and including an axially movable portion connected to said sleeve to move said sleeve axially of said shafts, resilient means connected to said sleeve to oppose movement thereof by said motor, means for supplying fluid under pressure to said motor, an arm connected to said sleeve having a passage communicating with said chamber and terminating in an outlet port, a valve arm connected to one of said shafts for angular movement thereon, a valve on said arm movable toward and away from said port.

8. Spark adjustment mechanism for an internal combustion engine comprising a drive shaft adapted to be driven from a rotating part of the engine, a timing cam shaft disposed coaxially with respect to said drive shaft, a sleeve coupling said shafts together and having differently angled spline connections with both to effect angul'ar movement of said control member relative to the,

shaft on which it is carried.

9. Spark adjusting mechanism for an internal combustion engine having an oil pump comprising a drive shaft adapted to be driven from a rotating part of the engine, a timing cam shaft disposed coaxially with respect to said drive shaft, a sleeve coupling said shafts together and having differently angled spline 1 connections with both to effect angular adjustment between said shafts upon axial movement of said sleeve, a control member carried by one shaft for rotation therewith and for angular adjustment relative thereto, and servo mechanism including fluid pressure actuated motor means adapted to be supplied with oil under pressure from said oil'pump connected to said sleeve-axially the amount required to produce angular movement between said shafts to correspond to angular movement of said control member relative to the shaft on which it is carried, 1

10. Spark adjusting mechanism for an internal com bustion engine comprising a drive shaft adapted to be driven from a rotating part of the. engine, a timing cam shaft disposed coaxially with respect to said drive shaft, a sleeve coupling said 'sha ftsvtogether and having differently angled spline connections with both toQetfect angular adjustment between said Lshafts ,upon' axial movement of said sleeve, a control valvecarried. by one shaft for rotation therewith and for angularfadjustment relative thereto, fluid pressure actuated motor means connected to said sleeve to move said sleeve axially, resilient means opposing movementof said sleeve by .said motor means, an arm carried by said sleeve, having a,fluid discharge passage communicating with said motor rme ansfand terminating in a port adjacent saidvalve member, .and means responsive to a variable engine condition for moving said valve member relative to said one shaft. f i

11. Structure as defined in claim '10 in which said motor means comprises an annular chamber surrounding the axis of said shafts.

12. Structure as defined in claim 11 in which said chamber comprises an annular flexible diaphragm connected to said sleeve.

' l3. Spark adjusting mechanism for an internal combustion engine having an oil pump comprising a drive shaft adapted to be driven from a rotating part of the engine, a timing cam shaft disposed coaxially with respect to said drive shaft, a sleeve coupling said shafts together and having differently angled spline connections with both to effect angular adjustment between said shafts upon axial movement of said sleeve, a control valve carried by one shaft for rotation therewith and for angular adjustment relative thereto, fluid pressure actuated motor means adapted to be supplied with oil under pressure from said oil pump connected to said sleeve to move said sleeve axially, resilient means opposing movement of said sleeve by said motor means, an arm carried by said sleeve having a fluid discharge passage communicating with said motor means and terminating in a port adjacent said valve member, andmeans responsive to a variable engine condition for moving said valve member relative to said one shaft.

14. Spark adjusting mechanism for an internal combustion engine having an oil pump comprising a driving Shaft adapted to be driven from a rotating part of the engine, an ignition timing cam shaft disposed coaxially with said driving shaft, a sleeve coupling said shafts together and having differently angled spline connections therewith and slidable axially of said shafts to eflect rela- 7 tive angular adjustment Wliiife maintaining a driving coupling relation therewith, fluid pressureactu'ated motor means operatively connected to said sleeve and adapted to be connected to the oil pump of the ngine, and valve means responsive to a variable engine condition for con' trolling said motor means.

15. Mechanism as defined in claim 14 inwhich said valve means comprises first means defining a valve port and second means defining a valve member operatively associated with said port, one of said first and second means being connected to one of said shafts for rotation therewith, the other of said first an'd secondv means being connected to the other of said shafts for rotation therewith and for limited 'a'n'gular adjustment relative thereto' in accordance with variations in said variable condition.

16. Servo Inte'ch'a'ni'sm' for effecting angular adjasiment between a pair of 'roiaryalig'ned shafts comprising a sleeve splined to both ofsa id shafts with splines of different angularity, afiuid 'm'otor' operatively. connected to saidsleeve including a member defining a motor control port carried by said sleeve, '21 control valve carried by one of said shafts for rotatiofn'therewith and limited angular adjustment relativefthereto, mea'ns'fdr adjusting said valve angularly with 'r'espect to said one shaft toward andaway from saidport, the variations in pressure 2 in saidv fluid motor. 'oceasioned b y the change' in restriction' 'ofsaid port'by said lvalve resulting in axial movement of said sleeve and resulting angular adjustment 1 of said member relative to said v'alvej; p U g 17. Mechanism'l as defined, claim i motor is an el ipz aiisibleeliarilber motor mitting fluid to saidjbgoto '{,3 (Lin "vvh c exhaust 'port for,,fliiid"from said more 1s.- Mechanism as dfined in claim? 1 a means for admitting fluid to said motor comprises arestrieted pass'agefconn'ectedfto -a' source of high pressure fluid, and 'in whichi'esilien't' arec oii'r'lebted tofs'aid motor to appy forces, lie'reto tendin redue the volume of said clianiberl" i I 19. Servo mechanism for effecting angular adjbstment between a pair of aligned rotary shaft memberseomprising a sleeve member splined to both of said shaft members with spline sof difierent angularityjafluid motor operatively connected to said sleeve to'mov'e "said sleeve member axially, and valve means for controlling said motor comprising two relatively movable elements, each of which is mechanically connected to one of said shaft and sleeve members for relative movement therewith occasioned by axial movement of said sleeve member.

20. Servo mechanism for effecting angular adjustment between a pair of aligned rotary shaft members comprising a sleeve member splined to both of said shaft members withsplines of different angularity, a fluid motor operatively connected to said sleeve to move said sleeve member axially, and valve means for controlling said motor comprising two relatively movable elements, each of which is mechanically connected to one of said shaft and sleeve members, said elements being relatively movable to perform a valvii1g function angularly with respect to the axes of said members for relative movement therewith occasioned by axial movement of said sleeve member. 4 v

. 21. Servo mechanism for eflecting angular adjustment between a pair of aligned rotary shaft members comprising a sleeve member ,splinedto both of said shaft members with splines ofdiflierent angularity, a fluid motor operatiyely connected to said sleeve to move said sleeve member axially, and valve meansfor controlling said motor comprising two relatively movable elements, each of which is mechanicallyjconnected to one of said shaft and sleeve members, said elements being relatively movable toperform a;valving-iunctionangularly with respect to the axes-of said members-for'relative :move ment'the'rewith occasioned by axial movement of said sleeye member, said motor comprising an expanding chamber, restricted: passage Imeans for supplying, fluid 'under, pressure jtosaid chamber, ;and said valve means being :Qonne'cted 4 to chamben 1885 1,255,177 Kettering Feb. s, 1918 1,284,471 ""Schmid 1918 1,494,030 slam I May 13, 1924 "1,577,468 Ka'isung Mar. 23, 1926 1,919,717 Fuehrer July 25, 1933 2,427,407 Hill Sept. 16, 1947 2,558,165 Anderson June 26, 1951 2,698,010 1954 2,757,522 1956 Peterson Aug. 7,

control ;exhaust; of t from 4 said- 

